Cold storage units such as freezers are used for various purposes, including the storage of biological samples over short and long periods of time. For example, biological materials for transplantation such as blood, tissue, or plasma may require storage for short periods of time before use. In another example, biological cells such as DNA samples may be stored for longer periods of time. Conventional cold storage units may be cooled by mechanical refrigeration circuits or by other methods, including the provision of liquid nitrogen (“LN2”). One type of cold storage unit used to store biological samples is tank or chest storage freezers (hereinafter collectively referred to as “tank freezers”), which include a relatively large storage area accessed through an opening formed at a top end of the tank or chest. The storage area is filled with storage racks which may be pulled vertically out of the storage area through the opening to access the samples stored in the storage rack.
Conventional tank freezers are typically large in height, requiring steps or a stool to be provided for an operator to gain access to the opening at the top of the tank. As a result of the large size of these tank freezers, it can be difficult to reach into the storage area and have enough leverage, especially while standing on steps or on a stool, to lift and hold the storage rack at a particular height during retrieval of a desired sample from the storage rack.
Moreover, storage facilities for biological samples, for example, typically maintain a plurality of tank freezers. It will be understood that each separate biological sample that must be retrieved by an operator could be located in separate tank freezers, which necessitates repeated climbing and arduous work of lifting the pertinent storage racks out of each of the tank freezers. If an automated assist mechanism is provided to help open a door of the tank freezer or hold the storage rack, such automated assist mechanisms are typically permanently mounted on or about the tank freezer, thereby significantly increasing the space taken up by each of the tank freezers within a facility as well as significantly increasing the cost and maintenance needs for each tank freezer.
There is a need, therefore, for an apparatus and method that further simplifies the retrieval and storage process for storage racks located inside tank freezers.